<template>
  <div id="app">
    <nav>
      <van-nav-bar :fixed="true" :title="$route.meta.title">
        <template #left>
          <van-icon
            name="arrow-left"
            size="20"
            color="#000"
            @click="goBack()"
            v-show="showBack"
          ></van-icon
        ></template>
      </van-nav-bar>

      <router-view style="padding: 46px 0 0 0"></router-view>
    </nav>
  </div>
</template>
<script>
export default {
  data() {
    return {
      showBack: false,
      noBackRoutes: ["/home", "/my", "/category", "/shopcart"],
    };
  },
  created() {
    this.showBack = this.noBackRoutes.includes(this.$router.path);
  },
  watch: {
    "$route.path"(newVal) {
      this.showBack = !this.noBackRoutes.includes(newVal);
    },
  },
  methods: {
    goBack() {
      this.$router.go(-1);
    },
  },
};
</script>

<style>
#app {
  font-family: Avenir, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  background: rgb(255, 255, 255);
}

#nav {
  padding: 30px;
}

#nav a {
  font-weight: bold;
  color: #2c3e50;
}

#nav a.router-link-exact-active {
  color: #42b983;
}
</style>
